To make the HP you are seeking with a 250 is going to require it to rev considerably higher in the RPM range to produce its power compared to a 292 or longer stroke engine, even with a turbo. This is going to keep its operating RPM range in an area I wouldn't be comfortable with day in and day out with cast pistons. Probably 90% of any problems you will have with a street turbo engine is going to be related to piston/ring failure, either because of detonation, improper piston design even if using forged(top ring too high, crown thickness too thin, wrong material, etc...)and/or fuel management related issues causing piston failure(improper fuel delivery system, insufficient volume, etc...). So to start with, I would highly recommend a quality forged piston. And you'll likely need to get them custom to get the correct material, ring placement and crown thickness needed. Followed up by a premium ring package. The rest is just basic simple ABC's, like ARP rod bolts, main studs, head bolts or studs. Premium rod and main bearings are a necessity as well, but your machine shop can likely source those parts for you when the time comes, followed up by the required machine work to complete the build.
